Solar heating system

ABSTRACT

A self-contained apparatus for collecting, storing and transmitting solar heat includes an elongated insulated housing in which a quantity of heat retaining material is confined and a collector on one face of the housing which has a multi-layered glass face through which solar heat may pass and be collected upon a unique heat-collecting bed which is insulated from the ambient environment by the glass face. Conditioning pump means are provided within the housing to circulate conditioning air through the collector and the heat retaining material in the housing so that heat is transferred from the collector to the material in the housing. Specially designed and positioned ducts connect the collector to the interior of the housing in a manner such that air interchange between the collector and the interior of the housing is prevented except during operation of the conditioning pump. Both the collector and the interior of the housing are provided with appropriately positioned baffles to optimally expose the conditioning air to the heat collecting bed and to heat retaining material in the housing. Reflective solar amplifiers are pivotally connected to the housing in a manner such that they are movable from an open operative position wherein they reflect solar radiation into the collector and a closed protective position overlying the glass face of the collector. Utility pump means are also provided in the apparatus for withdrawing air from the interior of the housing and circulating it through a building structure to be heated thereby. The method of collecting, storing and transmitting solar heat includes the steps of absorbing solar heat on a collector surface wherein the collector surface is insulated from the ambient environment, passing air across the collector surface in a heat transfer process whereby the heat absorbed by the collector surface is transferred to the air, passing the hot air leaving the collector surface through a horizontal duct disposed at a lower elevation than the collector surface, and passing the hot air flowing from the duct into an elevated storage chamber containing material with heat absorbent and heat retaining characteristics whereby the heat in the hot air is transferred from the hot air to the material and retained by said material until it is removed therefrom by a relatively cool air flow.

United States Patent [191 Keyes et al.

[ July 15, 1975 SOLAR HEATING SYSTEM [75] Inventors: John Harold Keyes;Charles Irvin Strickland; Robert George Strickland, all of Nederland,Colo.

[73] Assignee: International Solarthermics Corporation, Nederland, Colo.

[22] Filed: Oct. 16, 1974 [21] App1.No.:515,207

Related U.S. Application Data [62] Division of Ser, No. 445.473. Feb.25. I974.

Primary E.tamincrWilliam F. O'Dea Assistant E.\'aminer-Peter D. FergusonAttorney, Agent. or FirmBurton. Crandell & Polumbus [5 7] ABSTRACT Aself-contained apparatus for collecting. storing and transmitting solarheat includes an elongated insulated housing in which a quantity of heatretaining material is confined and a collector on one face of thehousing which has a multi-layered glass face through which solar heatmay pass and be collected upon a unique heat-collecting bed which isinsulated from the ambient environment by the glass face. Conditioningpump means are provided within the housing to circulate conditioning airthrough the collector and the heat retaining material in the housing sothat heat is transferred from the collector to the material in thehousing. Specially designed and positioned ducts connect the collectorto the interior of the housing in a manner such that air interchangebetween the collector and the interior of the housing is preventedexcept during operation of the conditioning pump. Both the collector andthe interior of the housing are provided with appropriately positionedbaffles to optimally expose the conditioning air to the heat collectingbed and to heat retaining material in the housing. Reflective solaramplifiers are pivotally connected to the housing in a manner such thatthey are movable from an open operative position wherein they reflectsolar radiation into the collector and a closed protective positionoverlying the glass face of the collector. Utility pump means are alsoprovided in the apparatus for withdrawing air from the interior of thehousing and circulating it through a building structure to be heatedthereby.

The method of collecting, storing and transmitting solar heat includesthe steps of absorbing solar heat on a collector surface wherein thecollector surface is insulated from the ambient environment. passing airacross the collector surface in a heat transfer process whereby the heatabsorbed by the collector surface is transferred to the air. passing thehot air leaving the collector surface through a horizontal duct disposedat a lower elevation than the collector surface. and passing the hot airflowing from the duct into an elevated storage chamber containingmaterial with heat absorbent and heat retaining characteristics wherebythe heat in the hot air is transferred from the hot air to the materialand retained by said material until it is removed therefrom by arelatively cool air flow.

4 Claims. 27 Drawing Figures SHEEI 3 Fig. /2

x/ZE-Z TEMPERATURE SENSOR TEMPERATURE SOLAR HEATING SYSTEM REFERENCE TORELATED APPLICATIONS This application is a division of application Ser.No. 445,473 filed Feb. 25. I974.

BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates generally to a method and apparatus of collecting.storing and transmitting solar heat and more particularly relates to amethod and apparatus for heating building structures and the like.

2. Description of the Prior Art The tremendous energy output of the sunhas been recognized for many years and numerous attempts have been madeat harnassing this energy so that it can be converted into a usefulstate. For example, the sun's energy has been successfully convertedinto electrical energy with solar batteries and similarly. the sun'senergy has been converted into heating systems by socalled solar stoves.furnaces and the like. The solar furnace apparatusses. however. havebeen typified by extremely large collector plates covering largeportions of the roof structure of a building to be heated with theapparatus and large storage chambers usually in the substructure of thebuilding wherein the heat is stored after having been transferred fromthe collector by a liquid fluid medium. The heat in the storage chamberis then circulated through the building structure by a separate fluidflow.

These systems. which have not only been unwieldly and very expensive toinstall. have proven to be very inefficient in that there is anexcessive heat loss when transferring the solar heat from the collectorto the removed storage chamber. Furthermore, these systems have not beencapable of being easily installed in existing building structures andhave not been devised to cooperate as an auxiliary heating unit to theconventional forced air heating systems commonly found in buildingstructures.

Typical examples of prior art solar heating systems may be found in theJune. 1973 and October. 1973 issues of Popular Mechanics magazine and inthe May. 1973 issue of Popular Science magazine.

OBJECTS OF THE INVENTION The present invention has for its primaryobject the provision ofa new and improved method and apparatus forcollecting. storing and transmitting solar heat.

It is another object of the present invention to provide a compact.selfcontained solar heating unit which can be positioned cxteriorly ofabuilding structure and with minimum time and expense connected to thebuilding structure so as to convert solar radiation into heat formaintaining a desired temperature within the building structure.

It is another object of the present invention to provide a new andimproved solar heating system which is readily connectecd into anexisting forced air heating system so as to serve as an auxiliaryheating system with minimum alteration to an existing buildingstructure.

It is still another object of the present invention to provide a new andimproved solar heating system which can also serve as a cooling systemwith minimal physical or mechanical alterations.

It is another object of the present invention to provide a solar heatingunit which utilizes a small and compact heat collector yet has thecapacity for adequately heating typical residential building structures.

It is another object of the present invention to provide a solar heatingapparatus having a reflective panel to increase captured solar radiationand which can also serve as a protective covering for the collectorportion of the apparatus in inclement weather conditions.

It is another object of the present invention to provide a solar heatingmethod and apparatus wherein conventional valve means between acollector and storage chamber of the apparatus are eliminated throughthe unique positioning and types of air transfer ducts and baffles.

It is another object of the present invention to provide a hot air solarfurnace in which baffle members are positioned on the collector and inthe heat storage chamber to desirably circulate air in obtaining optimumtemperature outputs from the unit.

It is another object of the present invention to provide a hot air solarfurnace in which air is transferred from a solar heat collector to astorage chamber with a minimum of heat loss and removed from the storagechamber and transmitted into a building structure with a minimum heatloss.

It is another object of the present invention to provide a hot air solarfurnace which has above ground heat storage eliminating the need forcostly and disfiguring excavation.

It is another object of the present invention to provide means tocontainerize heat storage with a new and simplified framing technique.

SUMMARY OF THE INVENTION The foregoing and other objects are obtained inac cordance with the present invention whereby solar heat is collectedand stored in an integrated compact unit which is capable of generatinga heat flow equal to or surpassing those of much larger unwielding unitswhich have been typical of prior art solar heating units. The solarheating apparatus of the present invention is self contained in anelongated housing preferably of triangular transverse crosssectionalconfiguration. This configuration has been found to allow a maximumquantity of heat retaining material, such as gravel. to be stored in theapparatus with a minimum of structural reinforcement. The housing isbasically constructed of two rectangular top panels, a rectangularbottom panel. and two triangular end panels which are interconnected todefine an enclosed storage chamber for the heat retaining material. Thepanels are each laminated in such a manner as to give both structuralstrength and the required insulating qualities for maintaining thetemperature of the heat retaining material in the storage chamber. Acollector unit is mounted upon one of the top panels of the housing soas to be inclined relative to the vertical in a position to receive themaximum heat from the Winter sun.

The collector unit is uniquely designed to absorb solar radiated heatand retain the heat by converting the heat waves. which will readilypass through transparent glass or plastic panes on the collector face,into long wave heat radiation which will not readily pass back throughthe glass or plastic panes on the face of the collector. The solar heatis absorbed on a base panel of the collector which emits relatively longwave heat radiation that becomes trapped in the collector. The basepanel of the collector has a plurality of forwardly opening cups whichserve to increase the heat absorption and emission capability of thecollector. Depending upon the material from which the cups are made,they usually will not retain the heat imparted thereto by the solarradiation for extended periods of time; accordingly, air is circulatedthrough the collector to transfer the heat absorbed by the cups into thestorage chamber of the apparatus wherein the gravel material not onlyabsorbs the heat carried by the air but also retains the heat forextended periods of time due to inherent heat retaining characteristicsof gravel and its inherent restriction of convection. The air whichpasses through the collector and into the storage chamber isre-circulated through the collector so as to continuously transfer heat,when desired. from the collector to the storage unit. For purposes ofthe present disclosure, this circulating air will be referred to ascondi tioning air. Since it is important to the optimum operation of theunit that the conditioning air be equally exposed to the entire base ofthe collector, a series of baffles are provided in the collector todirect the air stream through a series of reversing bends. Similarly.bafflcs are provided in the storage chamber to direct the conditioningair throughout the entire quantity of gravel in the storage chamber.

A conditioning air pump is positioned within the storage chamber toeffect the desired conditioning air flow. The air is passed from thestorage chamber to the collector and back into the storage chamberthrough inlet and outlet ducts which are positioned at an elevationbelow both the storage chamber and the collector so that when the pumpis not in operation. the hot air which is lighter than cold air. andtherefore urged to the top of the respective components of theapparatus. will not be able to freely flow between the components sothat the ducts establish thermal traps that avoid the necessity ofrelatively expensive valve means to accomplish the same purpose.

A reflector panel is hinged to the framework of the housing along anedge of the collector unit so that by opening the reflective panel, thesolar heat radiation being absorbed by the collector unit is increased.This reflective panel is designed so that in a closed position itoverlies the collector unit and thereby protects the relatively fragileglass from detrimental environmental elements such as hail. sunlight inSummer months, and the like.

The heat retained by the heat retaining material in the storage chamberis transferred into an adjacent building structure or the like by autility pump which may also be positioned within the storage chamber andconnected to the building structure by suitable insulated duct workhaving outlets for selectively distributing the hot air through thebuilding structure. This air flow. which will be hereinafter referred toas the utility air flow, is circulated back through the storage chamberin a manner so as to obtain a maximum heat transfer from the heatretaining material to the air and in a manner such that the utility airis not short circuited and directed through the collector with theconditioning air unless both pumps are operating simultaneously. As willbe explained in more detail hereinafter, this is accomplished bypositioning the inlet and outlet ducts for both the conditioning aircircuit and the utility air circuit on appropriate sides of the bafflemembers within the storage chamber.

As will be more fully appreciated hereinafter. the unit is ideallysuited for connection to an existing forced air heating system in abuilding structure so as to serve as an auxiliary unit to the forced airheating system even though in many instances. the solar heating unit issufficient in itself to provide the necessary heat for the buildingstructure.

According to the method of the present invention. heat is first absorbedfrom the sun on a collector surface wherein the collector surface isinsulated from the ambient environment and internal air is passed acrossthe collector surface in a heat transfer process so that the heatabsorbed by the collector surface is transferred to the internal air.The air is then passed through a duct which is lower than the collectorsurface into a raised storage chamber wherein it is directed throughheat absorbent and heat retaining material in the storage chamber sothat the heat in the hot air is transferred to the material in thestorage chamber. The heat retained by the material in the storagechamber is transferred into a building structure by directing a utilitystream of air through the material in the storage chamber and into thebuilding structure wherein it is distributed as desired throughout thestructure.

Other objects. advantages and capabilities of the present invention willbecome more apparent as the description proceeds taken in conjunctionwith the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the solarheating apparatus of the present invention with the reflector panelshown in an open position.

FIG. 2 is a perspective view of the solar heating unit of FIG. I withthe reflector panel in a closed position.

FIG. 3 is a perspective view of the solar heating unit of the presentinvention as viewed from the reverse side of FIG. 1.

FIG. 4 is an end elevation of the solar heating unit of FIG. I.

FIG. 5 is a side elevation of the solar heating unit of FIG. I showingthe collector unit.

FIG. 6 is an enlarged vertical section taken along line 6-6 of FIG. 4.

FIG. 7 is an enlarged vertical section taken along line 7-7 of FIG. 5.

FIG. 8 is an enlarged fragmentary vertical section illustrating theconnection of a top panel of the solar heating unit to the bottom panel.

FIG. 9 is an enlarged fragmentary section illustrating the connection ofan end panel of the solar heating unit to the bottom panel.

FIG. 10 is a section taken along line l0-I0 of FIG. 6.

FIG. II is an enlarged fragmentary vertical section taken along lineIIII of FIG. 6.

FIG. I2 is an enlarged section taken along line 12-12 of FIG. 5.

FIG. I3 is a vertical section taken along line Iii-13 of FIG. 5.

FIG. I4 is a vertical section taken along line 1414 of FIG. 5

FIG. 15 is a section taken along line 15-15 of FIG. 4.

FIG. 16 is a section taken along line 16l6 of FIG. 5.

FIG. I7 is a section taken along line l7--l7 of FIG. 5

FIG. 18 is a diagrammatic horizontal section illustrating the floor planof the solar heating apparatus of the present invention.

FIG. 19 is an enlarged section taken along line l9l9 of FIG. 4.

FIG. 20 is a diagrammatic perspective view illustrating the air currentsthrough the storage chamber of the solar heating apparatus of thepresent invention.

FIG. 21 is a diagrammatic perspective view showing a modified form ofthe solar heating unit of the present invention.

FIG. 22 is an enlarged vertical section taken through an upper portionof a forced air furnace illustrating the connection of the solar heatingapparatus of the present invention to the forced air furnace.

FIG. 23 is a section taken along line 23-23 of FIG. 22.

FIG. 24 is a perspective view of a valve plate shown in FIGS. 22 and 23.

FIG. 25 is a circuit diagram of the connection of the solar heatingapparatus of the present invention to a conventional forced air furnacesystem.

FIG. 26 is a diagrammatic representation of the dual switch control forthe conditioning pump of the apparatus of the present invention.

FIG. 27 is an electrical schematic of the dual switch control of FIG.26.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The solar heating apparatus 28of the present invention includes a housing 30 defining an internalstorage chamber 32, a collector unit 34 mounted upon one face of thehousing 30, and a reflector panel 36 pivotally connected to the housingso as to be movable between an open position exposing the collector unit34 to the ambient environment and a closed protective position overlyingthe collector unit.

The framework for the apparatus includes three insulating rectangularpanels of substantially the same size which are interconnected alongtheir longitudinal edges to form an elongated housing of triangulartransverse cross-section. The three rectangular panels consist of twoinclined top panels 38:! and 38b and a floor panel 40 with the toppanels 380 and 38h forming an angle of approximately 60 with horizontal.Each of the top panels and bottom panel are laminated with conventionalplywood sheets 42 on opposite faces and an inner relatively thick core44 of an insulating material such as a rigid polyurethane foam. Theplywood panels are preferably painted or coated with a reflective paintsuch as a silver paint to better retain heat within the storage chamber.

The panels 38a. 38b, and 40 are connected along their edges with arelatively thin gauge angled metallic strip which is positioned to beself-tightening. Referring to FIG. 8. it will be seen that the loweredge of each top panel is tapered to fit flush against the horizontaltop surface of the bottom panel 40 and an angled metallic strip 46,FIGS. 8 and l3, is positioned along the outer edge of the top and bottompanels 380 and 38b so as to have a horizontal leg 48 which lies betweenthe panels and an upwardly inclined leg 50 which is flush with the outersurface of the top panel. Conventional fasteners, such as of the screwtype, connect the horizontal leg with the bottom panel and the upwardlyinclined leg with the top panel. These fastening strips 46 extend alongthe length of the bottom of the panels to securely and reliablyinterconnect the panels. The bottom panel extends beyond the lower edgeof the top panel 38b for a reason which will become clear later.

At the juncture of the upper edges of the top panels 380 and 38b, one ofthe top panels 38a extends across the upper end of the other top panel381) and is bevelled at its outer end so as to form a angle therewithand establish a smooth juncture of the two panels. The plywood laminate42 on the outer surface of each of the top panels extends upwardly tothe uppermost point of the housing and an angle iron strip 52 is placeddownwardly over the juncture of the two outermost plywood sheets toextend along the length of the panels. This angle iron strip 52 issuitably fastened to the respective top panels, such as with screw typefasteners, to reliably secure the panels along the top edges thereof.

Triangular shaped end panels 54 and 56 are secured to the end edges ofthe top and bottom panels 380 and 38b of the housing in a manner whichis best illustrated in FIG. 9. There it will be seen that the end panels54 and 56 extend downwardly to the lower edge of the bottom panel 40 andlikewise extend outwardly to the outer edges of the top panels 38a and38b to completely cover the end edges of the top and bottom panels. Theend panels actually extend beyond the to panel 3817 at 58, FIGS. 12 and19, for a purpose to be described later. The end panels are constructedidentically to the top and bottom panels in that they are laminateshaving outer layers 60 of a rigid material such as plywood and an innerinsulating rigid foam core 62. The end panels are connected to the topand bottom panels by angled metallic strips 64, FIG. 9, which extendalong the junctures of the panels and are fastened thereto as withscrew-type fasteners in a self-tightening manner. Each end panel has aremovable door 66 closing an opening 68 therein which providesselectable access to pump containing compartments 70 and 72 in thestorage chamber 32 which will be described later.

A water-repellant sheet metal covering 74 is pro vided over the toppanel 38a and the end panels 54 and 56 so that these panels will beprotected from deterioration by moisture in the ambient environment.

The top, bottom and end panels cooperate in confining a heat retainingmaterial 76 such as gravel in a manner such that the weight of thegravel does not place excessive outward pressure on the housing. Inother words, since gravel is naturally piled with inclining sides, thepressure on the top walls 380 and 38b of the housing, since they too areinclined, is minimal. In the preferred form. the heat retaining material76 is a granite rock of approximately 1% inches in diameter so that thespaces between the rock particles are sufficient to allow the flow ofair through the storage chamber. A fill opening 78, FIGS. 3 and 6, isprovided near the top edge of one of the top panels so that gravel canbe poured through the opening to fill the storage chamber. An insulateddoor 80 removably seals the opening 78 during operation of theapparatus.

The storage chamber 32 of the apparatus has a plurality of baffles orbarrier plates 81, 82 and 84 positioned therein to encourage the desiredcirculation of air through the gravel material as will be described inmore particularity later. The baffle members include two upstandingbaffle members 80 and 82 of trapezoidal configuration which are flushwith the bottom wall and extend slightly over half the height of each ofthe top panels thereby separating the lower portion of the storagechamber into two end sections 86 and 88 and a central section 90, FIGS.6 and 20. The third depending baffle member 84 is suspended from theupper portion of the top panel members at approximately theirlongitudinal center and is of triangular configuration to fit flushlyagainst the inner surfaces of the top panel members and extend slightlyover half the height of the top panel members so as to overlap theupward extent of the upstanding baffles. Each of the baffle members issecured to the abutting top and bottom panel members by suitablefasteners 92, FIG. 10, which could be angle iron strips.

The reflector panel 36 in the preferred form includes a framework 37 inwhich three highly reflective sheets 39 of aluminum or the like areretained. The sheets may follow a modified parabolic curve toconcentrate solar radiation on the collector unit 34. The framework 37is pivotally mounted as by a hinge 41 to the floor panel 40 of theapparatus. The reflective sheets, of course, could be other suitablematerials such as mirrors, or the like, and if the mirrors were readilysusccptible to breakage, a large number of relatively small mirrorscould be mounted in the framework 37 so that replacement of damaged orbroken mirrors would not be a great economical burden.

The collector unit 34 which is probably best illustrated in FIGS. 1, 5,7 and 11-14, is of a size substantially the same as the top panels ofthe housing and is mounted directly on the outer face of the top panels38b. The collector unit includes an outer peripheral rigid frame 94. afront insulating glass portion 96, and a back heat accumulator portion98. The insulator glass portion and heat accumulator portion areseparated by a plurality of baffle members 100 and 102 which, as will beexplained hereinafter. serve to circulate air uniformly through thecollector.

The peripheral frame 94 abuts the inner surfaces of the extensions 58 ofthe end panels beyond top panel 38b so as to be insulated along theassociated two sides from the ambient environment and an elongated wedgeshaped insulating block 104 lies across and is attached to the topportion of the peripheral frame to insulate the top portion from theambient environment.

The insulating glass portion 96 of the collector unit consists. in thepreferred form, of three spaced layers 106a, 1061) and 1060 of glasswith each layer of glass having two coplanar glass or plastic panels108a 108b separated at the longitudinal center of the collector by acenter plate 110. Each glass or plastic panel is separated from theglass panel in the next adjacent layer by a rubber sealant strip 112which extends around the pcriphery of the panel. Referring to FIG. 17,the rubber sealant strips extending along the adjacent ends of the glasspanels at the longitudinal center of the collector are seen sandwichedwith the glass panels between an outer angle iron strip 114 which issecured as by a rivet to the center plate 110 and an inner channelmember 116 which is also secured to the center plate as by a rivet. Theperiphery of each glass panel is embedded along with the rubber sealantstrips 112 in a caulking compound 118, FIG. 17. to hermetically seal theperimeter of the insulating glass portion of the collector so that heataccumulated in the heat accumulator portion of the collector cannotescape back to the ambient environment around the periphery of the glasspanels. In FIGS. 11-13, the top, bottom and side edges respectively ofthe glass panels are seen similarly sandwiched between an outer angleiron strip 120 and an inner channel member 122 each of which are affixedin any suitable manner to the outer frame 94 of the collector unit.Accordingly, the glass panels 108a and 108!) on each half of the glassinsulating portion of the collector unit are retained in parallel spacedrelationship and are sealed around their periphery to prevent heat loss.

The heat accumulator portion 98 of the collector unit includes a planarback plate 124, preferably a sheet of black coated metallic coil or thelike which lies against or is affixed to the outer plywood sheet 42 ofthe top panel 38b. A plurality of forwardly opening cups 126, preferablyof cylindrical configuration and made of aluminum and coated black, arepositioned upon the black aluminum back sheet and define spaces 128therebetween which expose the back sheet 124. Again, preferably the cupsare coated or annodized in a black color as black is known to be thebest heat absorbent color. The cups may be loosely disposed upon theback plate 124 or could be secured thereto if desired. It will beappreciated that the cups enlarge the surface area of the heataccumulator 98 and thus the solar thermal energy capturing ability ofthe apparatus. In fact, by using cups which are approximately 2 inchesin length and 2% inches in diameter, the surface area of the heataccumulator will be increased approximately 4.75 times over that of aplanar heat accumulator. As clearly seen in FIGS. ll-l3, the forwardextent of the accumulator cups 126 is rearwardly spaced from theinsulator glass 96 defining an open space or passage 130 therebetweenthrough which air can freely pass. The baffle members 100 and 102 arepositioned within this space to direct the conditioning air currentsalong a predetermined path which fairly uniformly covers the entirearray or matrix of accumulator cups whereby a complete and effectivetransfer of heat from the accumulator cups to the air can be effected.

As best illustrated in FIG. 15, in the preferred form, there are threerising baffle members 100 which extend upwardly from the lower edge ofthe collector unit in uniformly spaced relationship and two dependingbaffle members 102 which extend downwardly from the top edge of thecollector unit into the centralmost spaces between the three risingbaffle members. Each of the baffle members extend approximatelythreefourths of the height of the collector. Referring to FIGS. 16 and17, these baffle members can be seen to be comprised of the back-to-backchannel members 132 and 116 with the channel members 116 on the centerbaffle 100 being those at the longitudinal center of the collector unitwhich support the adjacent center edges of the glass panels 108a and108b. The remaining baffle members, as shown in FIG. 15, serve tosupport the glass panels and additional rubber spacer sealant strips atintermediate locations so that the glass insulating portion 96 of thecollector unit is adequately supported and less prone to damage. Ofcourse, each ofthc baffles are secured to the back plate and theunderlying plywood sheet of the top panel by suitable fasteners.

Referring now to FIGS. 13-15 and 20, it will be seen that the lowerhorizontal portion of the frame 94 of the collector unit has rectangularopenings 134 and 136 at opposite ends thereof which communicate with thespace 130 between the glass insulator section and the heat accumulatorsection of the unit. The opening 134 is the inlet opening to thecollector while the opening 136 is the outlet opening. Air entering thecollector through the inlet opening 134 is confined in the space 130between the glass insulator portion 96 and heat accumulator portion 98and is directed along a path defined by the baffle members which passesthrough a series of reversing bends as indicated by the arrows in FIG.15, thereby forcing the air to pass across all of the accumulator cupsin the collector. Turbulence created by the configuration andpositioning of the cups assists in the more efficient transfer of heat.

Referring now to FIGSv 7, and 13-15, it will be seen that the inlet andoutlet pressure 134 and 136 respectively of the collector unit areconnected through rect angular passages 138 and 139 in an insulatingfoam block 140 to insulated ducts 142 and 143 which are cut or otherwiseformed in the floor panel 40 of the housing. The ducts 142 and 143 openinto the storage chamber 32 of the apparatus. The duct 142 communicatingwith the inlet opening 134 of the collector unit is in fluidcommunication with a conditioning air pump 144 mounted within theenclosed compartment 70 in the storage chamber. The pump 144 is also influid communication with an outlet 146 from the storage chamber via aduct 148. The ducts 143 and 148 each have screens covering theiropenings into the storage chamber 32 and each screen has a mesh sizeless than the size of the rock material stored in the storage chamber sothat the rock material cannot pass into the ducts. The screened opening150 connecting the duct 143 to the storage chamber, will hereafter bereferred to as the conditioning air inlet to the storage chamber whilethe screened opening 146 will be referred to as the conditioning airoutlet from the storage chamber.

It will, therefore, be seen that a circulating path is establishedthrough the collector and the storage chamber with the conditioning airpump serving as the means for effecting the desired circulation of theconditioning air. The conditioning air pump draws the air from thestorage chamber through the duct 148 which again is cut or otherwiseformed in the bottom panel of the housing so as to be at a level beneathboth the collector and storage chamber and open into the conditioningair pump compartment as well as into the end section 86 of the remainingopen area of the storage chamber so that air which has passed throughthe storage chamber is drawn downwardly into the duct 148 before passedthrough the conditioning air pump and subsequently into the collectorunit. The purpose for the three undcr-the-floor ducts 142, 143 and 148,is to prevent the free flow of air between the spaces connected by theducts eliminating the need for conventional fluid flow valves.

It is important that once the heat has been transferred from thecollector into the storage chamber that it not be allowed to escape fromthe chamber by convection during non-operation of the circulating pump.Since hot air rises to the top of the storage chamber and will not passdownwardly through any of the ducts connecting the storage chamber tothe collector unit and thereby allow heat to escape from the storagechamber. Accordingly. by placing the ducts at a level beneath both thestorage chamber and the collector unit. the hot air is prevented fromescaping from the storage chamber and the use of conventional andrelatively expensive valves are avoided. To insulate the ducts from theunderlying terrain on which the apparatus is supported. insulated pads152 are positioned beneath the ducts, even though a complete insulatingpanel approximately the size of the bottom panel could be used.Preferably, a vapor barrier 154 in the form of a corregated metal orplastic sheet would separate the insulat ing panel from the bottom paneland the ducts to prevent the ingress of moisture.

The flow of conditioning air through the storage chamber of theapparatus is best illustrated in FIG. 20 wherein it is seen that hot airleaving the collector unit through the outlet opening 136 emergesthrough the screened opening at the inlet end of the storage chamber andis forced to pass unwardly over the baffle member 82 into the heatretaining gravel and then follow a downwardly and upwardly reversingpath below and above the three baffle plates 80, 82 and 84 in thestorage chamber until it is drawn downwardly through the screened outletopening 146 at the opposite end of the storage chamber and subsequentlyblown by the conditioning pump into the collector unit through the inletopening 134. In this manner, the hot air being directed into the storagechamber from the collector unit is forced to pass through the storagechamber in such a manner as to come into contact with substantially allof the heat retaining gravel material in the storage chamber. It shouldbe realized that the inlet end of the storage chamber will normally besubstantially hotter than the outlet and during operation of theconditioning pump since the hot air entering the storage chamber willlose its heat to the gravel material as it passes through the storagechamber (provided that circulated air temperature is higher than storagetemperature) so that by the time the air reaches the outlet end of thestorage chamber it is somewhat cooler than when it entered the storagechamber.

In addition to the three aforedescribed underthefloor ducts 142, 143 and148, the apparatus has two additional under-the-floor ducts 156 and 158defining inlet and outlet ducts respectively of the utility air circuitso that the heat retained by the material in the storage chamber can betransferred via a flow of utility air through an adjacent buildingstructure. The inlet duct 156 for the utility air is seen in FIG. 7 tocomprise an elongated channel cut or otherwise formed in the floor panel40 of the apparatus and sealed by an insulating block 160 so as toextend beneath the lower edge of the top panel. The inner end of theinlet duct opens upwardly through the floor of the unit and has a screen162 covering thereover of a smaller mesh than the particle size of thegravel heat retaining material so as to prevent the gravel material fromfalling into the duct. The outer end of the duct opens upwardly andextends above the floor of the storage chamber and is connccted througha conventional air filter 164 to an elbow conduit 166 which is connectedvia an air flow conduit 168, FIG. 1, to a circulating duct system in thebuilding structure (not shown). The circulating duct system in thebuilding structure could be in an existing forced air furnace ductsystem and the heating apparatus of the present invention could beconnected thereto in a manner to be described in detail later. However,the solar system could have its own circulating duct system.

Similarly. the outlet duct 158 of the utility air circuit is formed inthe floor panel the same as the the inlet duct and has its inner endopening upwardly in fluid communication with a utility pump I70, FIGS.18 and 20, which is housed in the enclosed compartment 72 in the storagechamber at the diametrically opposite cornor from the conditioning pumpI44. The inlet of the utility pump opens through a screened opening I72in the adjacent upstanding baffle plate 82 so as to draw air from thecentral section of the storage chamber. The outlet duct 158 of theutility system also opens at its outer end through an insulated blockI74 and may be connected through an air filter (not shown) to a secondelbow conduit 176 and subsequently through an air flow conduit (notshown) to the circulating duct work in the building structure. It can,therefore, be appreci ated that a circulating utility air flow circuitis established through the storage chamber and the heating duct work inthe building structure whereby hot air can be drawn from the storagechamber and blown into the building structure wherein it may beselectively diverted through various vent openings into desiredlocations in the building structure.

As mentioned previously, the heat retaining gravel material 76 in thestorage chamber is hottest at the inlet end of the storage chamber withrespect to the conditioning circuit and progressively becomes relativelycooler toward the outlet end. It is, therefore. desirable that theutility air flow, or that air which is directed into the buildingstructure. is withdrawn from the storage chamber at the hot end or theinlet end thereof and for this reason the utility pump which withdrawsair from the storage chamber and directs it into the building structureis positioned at the hot or inlet end in the section 88 of the storagechamber. However. to prevent air entering the storage chamber from thecollector unit through opening 150 from being withdrawn directly by theutility pump 170, the inlet 172 to the utility pump is positioned on theopposite side of the upstanding baffle plate 82 from the opening 150 sothat the hot air entering the storage chamber is forced to begincirculating and thereby transferring its heat into the gravel materialwhereby this heat will be retained by the gravel material and can bereadily withdrawn when the utility pump is in operation. In other words.by positioning the inlet 172 to the utility pump on the opposite side ofthe baffle plate 82 from the outlet of the collector, a short circuit inboth the utility and conditioning air flows is avoided.

So that the utility air entering the storage chamber will have adequatetime to absorb heat from the gravel storage material before it iswithdrawn from the storage chamber by the utility pump. it is desirablethat the inlet 162 to the storage chamber in the utility circuit bepositioned as far away from the utility pump as possible. However. theinlet in the utility circuit is preferably not placed closely adjacentto the outlet 146 from the storage chamber in the conditioning circuitso that the air does not flow directly into the outlet of theconditioning circuit but rather flows toward the utility pump I70 andthus toward the hot end of the storage chamber in a counter-flowdirection relative to the conditioning air circuit except when bothpumps are in simultaneous operation. For this reason. the inlet I62 ofthe utility circuit has been positioned on the opposite side of theupstanding baffle plate 80 so that this air will migrate toward the hotend of the apparatus beneath the center baffle plate 84 and will notrise and pass over the upstanding baffle plate 80 and thereafter passinto the outlet I46 ofthe conditioning circuit. Accordingly. thisrelative relationship of the inlet 162 in the utility circuit to theoutlet I46 in the conditioning circuit prevents short circuiting of theutility air flow and encourages the air to flow in the desireddirection.

It should be appreciated that the apparatus is designed so that ifdesired. the storage chamber can be essentially by passed whereby hotair can be circulated through the collector and the building structurewith minimal contact with the heat retaining material. In this mannerheat from the collector is transferred substantially directly into thebuilding structure. This can be best understood by reference to FIG. 20wherein it will be seen that if both the utility pump I and theconditioning pump 144 are operated simultaneously, air leaving thecollector and entering the storage chamber through opening 150 will passupwardly over the baffle member 82 and will be immediately drawn intothe inlet I72 of the utility pump wherefrom it will be circulatedthrough the duct work in the building structure. In other words, whenthe hot air enters the storage chamber and passes over the baffle member82, the low pressure existing at the inlet 172 to the outlet pump duringoperation of the utility pump attracts the hot air so that it does nottake its normal circulating path through the heat retaining material inthe storage chamber. After the air has circulated through the duct workin the building structure it enters the storage chamber through inletI62 and is drawn over baffle member into outlet I46 from the storagechamber whereby it is cycled into the conditioning pump I44 and into thecollector through the inlet 134 to the col lector. Thus it will be seenthat a closed circulating path directly connecting the collector to theduct work in the building structure, with minimal contact with the heatretaining material 76, is established by simultaneous operation of theconditioning and utility pumps.

The conditioning pump 144 in the preferred form is automaticallycontrolled by a dual control system illustrated in FIGS. 26 and 27. Aresistant temperature detector in the form of a probe 178, FIG. 18, ispositioned in the storage chamber near the center thereof and a secondresistant temperature detector in the form of a probe I79, FIG. 15, ismounted in the collector near the outlet from the collector so that eachis disposed to sense the temperature at the respective locations. Thetemperature detectors are connected through a comparator circuit,illustrated in FIG. 27, to the control switch of the conditioning pump.The comparator circuit, as will be explained hereinafter, is used tocompare the temperatures of the detectors I78 and 179 and to switch theconditioning pump on when the temperature of the detector I79 equals orsucceeds by a predetermined amount the temperature of detector 178. Byso controlling the operation of the conditioning pump, breakage of thecollector glass panels by thermal shock is alleviated. the use of lessinsulation at the collector glass panels is allowed since heat isextracted rapidly from the collector cutting heat loss through the glasspanels, and the life of the conditioning pump is extended due to lesscycling. While other comparator circuits could be utilized. in thepreferred form, the comparator circuit is in the form of a conventionalwheatstone bridge where identical resistors RI and R2 are connected inthe bridge with a third resistor R3, the detector I78, the detector 179,and :l rhcnstat ISI. The operation of the whcatstonc bridge circuit isconventional with the rheostat 18] serving to adjust or regulate thetemperature differential between detectors 178 and 179 desired foroperation of the conditioning pump. It will, therefore, be seen thatwith the dual control system, the temperature in the storage chamber isautomatically maintained or raised during normal weather conditions.

As mentioned previously, the aforedescribed heating apparatus can beeasily connected into an existing forced air furnace system in abuilding structure. Referring to FIGS. 22-25, the manner in which theheating apparatus can be connected to a forced air furnace system isillustrated. Looking first at FIG. 22, the upper end ofa typical forcedair furnace unit 180 is illustrated having heat exchangers 182 in a heatexchange portion 184 of the unit and a plenum chamber 186 above the heatexchange portion 184 wherein the hot air emitted from the forced airfurnace unit is directed into the circulating duct work in the buildingstructure for desired distribution through the building structure. Anoutlet conduit 188 in the utility circulating system of the solarheating apparatus 28 of the present invention is connected to the plenumchamber I86 of the forced air heating unit through an opening I90 in oneside thereof so that the air entering the plenum chamber from the solarheating apparatus will pass into the plenum chamber wherefrom it can bedirected into the circulating duct work in the building structure fordesired distribution throughout the structure. To prevent this air frompassing downwardly into the forced air furnace when the forced airfurnace is not in operation, a series of valve plates 192 are pivotallymounted across the open upper end of the heat exchange portion 184 ofthe forced air furnace apparatus so that in normal conditions when theforced air furnace is not in operation, these valve plates lie in theclosed solid line positions of FIGS. 22 and 23. The valve plates includea rectangular planar section 194 with a pivet rod I96 along onelongitudinal edge. The pivot rod extends beyond the ends of therectangular planar section so that the ends of the rod can be journalledin suitable bearing members 198 shown as U-shaped brackets in FIG. 23,to pivotally support the valve plates in a horizontal disposition. Thewidth of the rectangular planar section of each plate is such that theplate overlie the pivot rod of the next adjacent plate whereby when theplates are in their closed positions, the outlet from the heat exchangeportion of the forced air furnace is blocked. Accordingly. air enteringthe plenum chamber from the solar heating apparatus 28 through theconduit 188 cannot flow downwardly but must flow upwardly and into thecirculating duct work for desired distribution through the buildingstructure.

When the forced air heating apparatus is in operation. however, the airbeing blown upwardly through the heat exchange portion 184 and into theplenum chamber 186 is sufficiently strong enough to pivot the valveplates 192 about their pivot rods so that they open into the dotted lineposition of FIG. 22 thereby allowing the air to pass into the plenumchamber and subsequently into the circulating duct work of the buildingstructure. Pin stops 200 are provided for each valve plate to limit thepivotal movement of the plate. In this manner, the solar heating unitcan be connected directly into the forced air heating unit and neithersystem will inhibit proper functioning of the other. Accordingly, whenit is desired to operate the forced air furnace apparatus, it willoperate independently of the solar heating unit and when the solarheating unit is up erated, it can operate independently of the forcedair heating apparatus.

Referring to FIG. 25, a schematic control circuit diagram is shown withthe solar furnace system and a conventional forced air furnace systemconnected in a complementary fashion. It will be seen that as isconventional, a step-down transformer 204 converts the volt AC. inputinto a 24 volt potential which is placed on the coil 206 in a forced airgas furnace relay 208. The thermostat 210 in the house or buildingstructure is also connected between the transformer 204 and the coil 206so that the coil is not energized unless the house thermostat is closed,such has when the temperature in the house is below a preselectedtemperature. When the coil in the forced air gas furnace relay isenergized, it closes a switch 212 which places a potential on the forcedair furnace blower 214 and on a thermo stat 216 in the solar furnacestorage chamber. The forced air furnace blower, however, will notoperate unless a furnace control switch 218 which is also temperaturecontrolled and which is positioned within the forced air furnace isclosed. This furnace control switch, however, does not close until thetemperature within the forced air furnace is above a preselected level.The solar furnace storage chamber thermostat 216 is a double-throwswitch so that when the temperature in the storage chamber is below apreselected temperature, the forced air furnace gas valve 219 isenergized thereby causing the forced air furnace to heat and once thetemperature of the furnace unit is above a preselected level, thefurnace control switch closes thereby energizing the forced air furnaceblower so that the hot air from the forced air furnace will be circulated through the building structure. However, if the temperature withinthe solar furnace storage chamber is above a preselected level, thesolar furnace storage thermostat rather than energizing the forced airfurnace gas valve 219 energizes the solar furnace blower or utility pumpso that the utility circulating air in the solar furnace is operated toheat the building structure. It will be appreciated, that in thismanner, the conventional forced air heating system and the solar heatingsystem of the present invention are used to sup plement each other anddepending upon the solar radiation in the particular area in which theunit is in operation, the solar furnace system can be predominately usedwith the forced air furnace system only as a backup during unusualweather conditions. The operaton of the conditioning pump 144 isautomatically controlled by a dual sensor thermostat.

Referring to FIG. 2], it is seen that additional reflector panels havebeen mounted upon the solar heating unit 28 to increase the solarradiation received by the collector unit 34. As illustrated, reflectorpanels 220 are pivotally mounted along each side of the collector unitand a reflector panel 222 is mounted along the top edge of the collectorunit to cooperate with the reflector panel 36 previously described asbeing connected along the bottom edge of the collector unit. Of course,during inclement weather conditions, when it is desirable that the glassor plastic insulator 96 on the collector unit be covered, each of thereflector panels can be folded inwardly into protective overlyingface-to-face relationship with the collector unit.

It has been found by building the solar heating unit of the presentinvention in accordance with the previous description that the units canbe made in a very compact manner and of a size to be positioned in afairly inconspicuous manner adjacent to a building structure. such as ahome. without materially detracting from the appearance of the home. infact, it has been found that the unit can be placed in a normal sizedbackyard without taking up unreasonable ground space.

In a test unit, which was not placed in an optimum position forreceiving maximum solar radiation, each of the top and bottom panels ofthe unit, the reflector panel, and the collector unit were approximately8 feet by 12 feet as opposted to the prior art arrangements whereinsubstantial portions of the roof of the building structures were neededto collect adequate solar radiation to heat the building structure. Byutilizing the thermal cups in the collector unit, it was found that thesolar heat absorbed by the unit was equivalent to a conventional planarcollector unit that was 16 feed by 28 feet, or the solar absorbingcapacity of the collector of the present unit was found to beapproximately 4.75 times that of a conventional planar collector notutilizing the accumulator cups. When using grave] of approximately 1%inches in diameter particle size. the unit has been found capable ofobtaining temperatures at the hot end ofthe storage chamber of around300F, a mean storage chamber of approximately 250F, and was found tolose only l /1" to 5 (depending upon outside ambient tempcrature) perday when the conditioning and utility pumps were not operated. Sincetypical forced air furnace systems only obtain mean temperatures ofabout 130 in the plenum chamber, it will be appreciated that due tohigher operating temperatures, the solar unit utility pump does notrequire as long a duration of operating cycles as a forced air furnaceto maintain a given temperature in the building structure with the sameoutside ambient temperatures. Since a particular storage materialinherently absorbs and emits heat at approximately the same rate, andsince the rate at which heat is exposed to the storage material isexcessive in the present apparatus of the absorptive capability of thestorage material, the rise and fall of the storage material temperatureoccurs at the same rate given similar pump capacities of the utility andconditioning pumps, and not unusual temperature differentials in thebuilding structure being heated and exclusive of simultaneous conductionlosses through the walls of the apparatus.

While the foregoing description has been directed to the heatingcapability of the apparatus of the present invention, it should beappreciated that the apparatus is also capable of cooling buildingstructures and therefore has a dual capability. When using the apparatusto cool a building structure, it is connected to the building structurein the same manner as previously described but instead of storing solarheat during daylight hours, the unit is closed during the daylight hourswith the reflector panel 36 lying over the collector unit 34 to preventsolar heat from being absorbed by the collector unit. Then, when the sunis not shining. the conditioning pump is then operated to circulate airthrough the collector and the storage chamber wherein heat is re movedfrom the storage material 76 or grave] in the storage chamber. After thegravel has been adequately cooled, and before the ambient air begins towarm up during daylight hours, the conditioning pump 144 is turned offthermostatically. When cool air is desired in a building structure. theutility pump is operated to circulate air through the relatively coolstorage mate rial to thereby remove heat from the building structure.

Although the present invention has been described with a certain degreeof particularity, it is understood that the present disclosure has beenmade by way ofexample and that changes in details of structure may bemade without departing from the spirit thereof,

What is claimed is:

1. in a solar furnace system having a solar furnace adapted to beconnected to a forced air furnace system wherein said forced air furnacesystem includes a forced air furnace with an outlet therefrom in fluidcommunication with circulating duct work, and wherein the outlet fromthe solar furnace is connected to the duct work at a locationimmediately adjacent to the outlet from said forced air furnace, theimprovement comprising at least one valve means normally closing saidoutlet from the forced air furnace and adapted to open said outlet whenair is emitted from the outlet of the forced air furnace.

2. In the solar furnace system of claim 1, wherein said valve means isat least one pivotally mounted plate and said outlet from the solarfurnace is positioned relative to said plate so as to blow air acrossthe pivotal mounting of the plate before crossing the plate itselfwhereby the plate is urged into its normally closed position when air isemitted from the outlet of the solar furnace.

3. in the solar furnace system of claim 1 wherein said valve meansconsists of a plurality of plate members pivotally mounted across thetop of the outlet from said forced air furnace so as to pivotal aboutparallel hori zontal axes, each plate member being of a size to overlapan adjacent plate member whereby the pivoted mounting of one platemember can support the free edge of an adjacent plate member to closethe outlet from the forced air furnace when air is not being emittedfrom the forced air furnace outlet.

4. In the solar furnace system of claim 3 further including stop membersaffixed to said duct work and positioned to engage respective ones ofsaid plate members to limit pivotal movement thereof when air is beingemitted from the outlet of the forced air furnace. l s: a:

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NO. Dated5: Inventor(s) John Harold Keyes et a1 It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

In the Abstract:

Column 2, line 12, before "heat" insert -the.

In the Specification:

Column 9, line 16, "pressure" should read -openings.

Column 9, line 5" after "before" insert being-.

Column 10, line 40, "underthe" should read --under-the Column 15, line17, "opposted" should read -opposed--.

Column 15, line 23, "feed" should read --feet-.

Signed and Bealcd this ninth Day of December 1975 '[SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner uflatentsand Trademarks

1. In a solar furnace system having a solar furnace adapted to beconnected to a forced air furnace system wherein said forced air furnacesystem includes a forced air furnace with an outlet therefrom in fluidcommunication with circulating duct work, and wherein the outlet fromthe solar furnace is connected to the duct work at a locationimmediately adjacent to the outlet from said forced air furnace, theimprovement comprising at least one valve means normally closing saidoutlet from the forced air furnace and adapted to open said outlet whenair is emitted from the outlet of the forced air furnace.
 2. In thesolar furnace system of claim 1, wherein said valve means is at leastone pivotally mounted plate and said outlet from the solar furnace ispositioned relative to said plate so as to blow air across the pivotalmounting of the plate before crossing the plate itself whereby the plateis urged into its normally closed position when air is emitted from theoutlet of the solar furnace.
 3. In the solar furnace system of claim 1wherein said valve means consists of a plurality of plate memberspivotally mounted across the top of the outlet from said forced airfurnace so as to pivotal about parallel horizontal axes, each platemember being of a size to overlap an adjacent plate member whereby thepivoted mounting of one plate member can support the free edge of anadjacent plate member to close the outlet from the forced air furnacewhen air is not being emitted from the forced air furnace outlet.
 4. Inthe solar furnace system of claim 3 further including stop membersaffixed to said duct work and positioned to engage respective ones ofsaid plate members to limit pivotal movement thereof when air is beingemitted from the outlet of the forced air furnace.